doc: updated test instructions to avoid external directory
doc: updated test instructions to avoid external directory

fprados/nipype,Leoniela/nipype,dgellis90/nipype,gerddie/nipype,iglpdc/nipype,grlee77/nipype,mick-d/nipype,dmordom/nipype,pearsonlab/nipype,mick-d/nipype_source,JohnGriffiths/nipype,FCP-INDI/nipype,FredLoney/nipype,sgiavasis/nipype,FCP-INDI/nipype,FredLoney/nipype,arokem/nipype,pearsonlab/nipype,christianbrodbeck/nipype,gerddie/nipype,grlee77/nipype,carlohamalainen/nipype,sgiavasis/nipype,Leoniela/nipype,fprados/nipype,sgiavasis/nipype,glatard/nipype,sgiavasis/nipype,carolFrohlich/nipype,JohnGriffiths/nipype,pearsonlab/nipype,carlohamalainen/nipype,Leoniela/nipype,rameshvs/nipype,blakedewey/nipype,glatard/nipype,carolFrohlich/nipype,mick-d/nipype,carolFrohlich/nipype,FredLoney/nipype,fprados/nipype,mick-d/nipype,mick-d/nipype_source,arokem/nipype,mick-d/nipype,christianbrodbeck/nipype,FCP-INDI/nipype,arokem/nipype,mick-d/nipype_source,arokem/nipype,iglpdc/nipype,carolFrohlich/nipype,dgellis90/nipype,pearsonlab/nipype,wanderine/nipype,JohnGriffiths/nipype,iglpdc/nipype,glatard/nipype,gerddie/nipype,gerddie/nipype,JohnGriffiths/nipype,grlee77/nipype,rameshvs/nipype,dgellis90/nipype,wanderine/nipype,blakedewey/nipype,FCP-INDI/nipype,glatard/nipype,grlee77/nipype,rameshvs/nipype,wanderine/nipype,wanderine/nipype,blakedewey/nipype,dmordom/nipype,blakedewey/nipype,rameshvs/nipype,carlohamalainen/nipype,dmordom/nipype,iglpdc/nipype,dgellis90/nipype